1. Field of the Invention
The present invention relates to a rear part structure for a vehicle, for installing a tailgate in a so-called mohican roof having a groove (mohican groove) extending in the forward and rearward direction of a vehicle at a connection portion between a roof panel of the vehicle body and a side frame thereof.
2. Discussion of Background Art
Conventionally, a hatchback tailgate composed of a hinge structure is provided in a recreation vehicle (RV) such as a minivan or a station wagon in order to easily place loads in the rear part of the vehicle. For example, refer to Japanese Unexamined Patent Publication No. 2001-105867 (paragraphs 0021 through 0022, and FIG. 12 and FIG. 13).
FIG. 1 is a view showing a prior art rear part structure of a vehicle, which is a sectional view showing the major parts in a state where the tailgate is closed.
As shown in FIG. 1, a tailgate 330 is installed so as to be vertically pivotable via a hinge 310 at the rear part 302 of a roof portion 301 of a vehicle body 300. A hinge pin 325 which becomes a rotating center of the hinge 310 axially supporting the tailgate 330 is disposed between the roof portion 301 and the tailgate 330. The hinge 310 is composed of a hinge base member 315 fixed on the roof portion 301 and a gate hinge member 320 fixed on the tailgate 330. The hinge 310 is installed at both left and right sides of the upper part of the gate opening portion 303 formed in the rear section 302 of the vehicle 300, and pivotally supports the tailgate 330 so as to open it in the form of a pop-up system.
The hinge base member 315 is a metal plate member which is roughly L-shaped in its side view. A fixing portion 316 at the base end side is firmly attached to an upper part 304 of the gate opening portion 303 of the vehicle 300 by means of a welding bolt 335, and a connection portion 317 at the tip end side is rotatably connected to the gate hinge member 320 by the hinge pin 325. The fixing portion 316 is fixed on a flat upper part 304 lower by a height L2 from the ceiling surface 305 of the roof portion 301.
The gate hinge member 320 is fixed, by a gate attaching bolt 340, on a roughly vertical attaching surface 332 where the fixing portion 321 at the base end side is formed on an upper part 331 of the tailgate 330, and a connection 322 at the tip end side is rotatably connected to the hinge base member 315 by the hinge pin 325.
When the tailgate 330 is opened, the tailgate 330 is turned in the direction of the arrow A centering around the hinge pin 325. At this time, parting 333 on the upper part of the tailgate 330 and the gate hinge member 320 are caused to turn integral with the tailgate 330, and the parting 333 turns in the direction of the arrow A and is caused to approach the fixing portion 316 of the hinge base member 315.
At this time, in order to prevent the parting 333 from being brought into contact with the roof portion 301, it is necessary for the hinge pin 325 to be disposed at a higher position by lengthening the arm length L1 at the hinge base member 315 which supports the gate hinge portion 320. By lengthening the arm length L1 of the hinge base member 315, it is necessary that, in the vehicle body 300, the length L2 from the installation plane of the upper part 304 on which the fixing portion 316 is provided to the ceiling surface 305 is lengthened, and the profile of the roof portion 301 is set in order to avoid the rotating locus of the parting 333 of the tailgate 330.
In line therewith, in the vehicle body 300, the thickness T1 from the upper end of the gate opening portion 303 in its upper direction to the ceiling surface 305 is increased, wherein the height H1 of the gate opening portion 303 in its upper direction is regulated, and the entire area of the gate opening portion 303 is narrowed. Therefore, in the gate opening portion 303, it becomes difficult to carry out loading a large load in or unloading the same from the luggage compartment because the height H1 is low.
Also, for a person in charge of loading or unloading, there is a fear that his or her head is brought into contact with the edge of the gate opening portion 303 during the loading or unloading since the inside upper end of the gate opening portion 303 is low.
In addition, where the tailgate 330 is attached to the vehicle body 300, it is possible to adjust the attaching position thereof in the top and bottom directions of the arrow B by making a through-hole 323, into which a gate attaching bolt 340 is inserted, into a slot longer in the top and bottom directions.
However, where the attaching position of the tailgate 330 is adjusted in the longitudinal (forward/backward) direction of the arrow C, since the fixing portion 316 of the hinge 310 is firmly fixed with rivets or welding bolts 335 so that the tailgate 330 does not raffle, it is necessary to modify the roof portion 301 of the vehicle body 300 or change the shape of the hinge 310. Therefore, with respect to the tailgate 330, it has been difficult to adjust the attaching position thereof in the longitudinal direction of the arrow C.
Further, an open stay (not illustrated) is provided between the tailgate 330 and the vehicle body 300. The one end of the open stay is supported at both sides of the tailgate 330 and the other end thereof is supported at both sides of the gate opening portion 303 in the vehicle width direction, respectively. And, the attaching position of the open stay (not illustrated) intervening between the tailgate 330 secured at the end portion in the vehicle width direction of the gate opening portion 303 and the vehicle body 300 is offset from the hinge 310 in the vehicle width direction of the tailgate 330.
Therefore, there is a possibility for the tailgate 330 to be deformed so as to be distorted due to a reaction force of the open stay (not illustrated). Deformation of the tailgate 330 adversely influences the assembling dimensions, wherein there is a problem in that it takes many working hours for adjustment of the dimensions and composition.
It is a first object of the invention to provide a rear part structure of a vehicle by which larger dimensions can be secured with respect to the top and bottom directions of the gate opening portion of the tailgate, with respect to hinge means for a tailgate.
On the other hand, since the open stay (not illustrated) maintains an opened state of a tailgate when the tailgate being a heavy load is opened upwards, there are many cases where the open stay intervenes between the vehicle body and the tailgate for supporting the tailgate. As has been described in Japanese Unexamined Patent Publication No.2000-158942 (Paragraph 0009 and FIG. 7), a damper stay may be listed as a detailed example of the open stay, which carries a function for relieving a force when manually opening the tailgate upwards. Open stays such as a damper stay may be provided at both side ends of the tailgate as a pair. However, in recent years, taking economical efficiency of a vehicle into consideration or taking convenience into consideration with respect to the open stay be coming an obstacle in loading or unloading, there are many cases where the open stay is provided only at one side end of the tailgate.
In the case where open stays are provided at both side ends, reaction forces received from the respective open stays are added to the tailgate uniformly at both the left and right sides when an opening or closing operation is carried out or the tailgate is fully opened. However, in the case of a tailgate for which an open stay is provided only at one side end portion, the reaction force is centralized only at the side where the open stay is provided. Resultantly, where the attaching positions of the above-described pair of hinge members are made completely symmetrical with respect to the left and right sides, there is a problem in that, when the tailgate is assembled in a vehicle body, the side where no open stay is attached falls due to its own weight and is deflected, and a level gap or deviation is apt to occur between the left and right sides of the tailgate.
In such cases, in the prior arts, adjustment work is required so as to absorb the above-described level gap or deviation when assembling the tailgate and open stays in the vehicle body. A method for employing a so-called expectancy allowance, for example, adding an adjustment shim to one hinge member, was adopted as a detailed example. However, the adjustment work using such a shim results in a lowering in work efficiency, in particular, assembling work under a premise of such an expectancy allowance accompanies a difficulty in view of quantitativity and stability, and requires skill to some extent. In addition, in a case of complex component composition such as a tailgate and open stays, etc., it becomes difficult to accurately analyze the expectancy allowance.
Therefore, it is a second object of the invention to provide a rear part structure of a vehicle which does not require any adjustment work of shims, etc., and can easily carry out assembling work of the tailgate.
Further, the tailgate is supported so as to be opened and closed by a tailgate hinge axially supported at the upper part of the opening portion. In Japanese Unexamined Patent Publication No. 2001-105867 described above, as shown in FIG. 2, a rear part structure that can vertically open and close a tailgate T by a tailgate hinge H axially supported at the rear end of a roof panel R so as to be rotatable is illustrated.
Conventionally, where a tailgate hinge is disposed outside a vehicle compartment, the tailgate hinge H is covered up by a spoiler SP or a resin-made garnish, as shown in FIG. 3, in view of the appearance of the vehicle or in order to avoid the exposure of the hinge to the outside of the vehicle. However, where the tailgate hinge H is covered up by the spoiler SP, etc., it is necessary to cover up the entirety of a tailgate hinge even for a tailgate hinge that seems to be sufficient to be partially outfitted in an attempt to secure harmony with respect to the entire appearance. For this reason, there is no way other than to employ a large-type resin component, wherein appearance matching with the surrounding components thereof becomes difficult, and there are some problems in that production costs are increased, and the number of steps is increased in the production process due to an increase in the number of components.
In addition, a tailgate hinge may be provided at the rear part of a vehicle or at the tailgate without using any outfitting components such as a spoiler, garnish, etc. For example, as shown in FIG. 4, the upper part of the roof panel R is formed to be bulge-shaped, and a tailgate hinge is accommodated in the bulge-shaped projection BG so that the tailgate is not exposed to the outside of a vehicle. However, in the case where the tailgate hinge is covered up at the rear part of a vehicle or at the tailgate side without using any outfitting components, the press-forming performance in production of roof panels may be worsened due to addition of some shapes onto the roof side, depending on the design shape. Therefore, it cannot be said to be convenient in view of design and production efficiency.
Further, a tailgate hinge may be disposed in a vehicle compartment. However, the appearance inside the vehicle compartment may be spoiled, although this depends on the positions of where it is disposed. Therefore, it is necessary to attach a hinge cover to cover up the tailgate hinge. For example, where a tailgate hinge is provided in the rear part of a vehicle compartment, it is necessary to attach a hinge cover in order to keep the appearance satisfactory inside the vehicle compartment. For this reason, the design inside the vehicle compartment is subjected to some limitations, resulting in inconvenience in production.
Therefore, it is a third object of the invention to provide a rear part structure of a vehicle, which attaches a tailgate hinge for axially supporting a tailgate to a roof panel without spoiling the vehicle appearance.